Several types of burglar alarm systems include a vibration or motion sensor device which is attached to a window pane in a building which is protected by the alarm system. The vibration or motion sensor device senses vibration or motion in a portion of the window pane when the window pane is broken or moved. The vibration or motion sensor conventionally is of the inertial type which includes a normally-closed switch which opens when subjected to sudden motion or vibration. The switch is electrically connected to an alarm system. Therefore, when the switch is opened an audible and/or visible alarm signal in the alarm system is actuated.
Conventionally, a vibration or motion sensor device in a burglar alarm system has been enclosed within a box-like housing which is attached to a window pane. The box-like housing is unattractive and is therefore ordinarily positioned in a most obscure location adjacent the edge and/or corner of the window pane. A vibration or motion sensor device which is positioned adjacent an edge and/or corner of a window pane is located in a position in which the sensor device is least sensitive with respect to the entire window pane and may not be capable of sensing window pane vibration or motion which is created by an experienced burglar.
It is an object of this invention to provide a window pane vibration or motion sensor device which is adapted to be attached to the central portion of a window pane so that the sensor device is located in a position of maximum vibration sensitivity.
It is another object of this invention to provide such a sensing device which has an attractive, pleasing appearance.
Another object of this invention is to provide such a window pane vibration sensor device which can be produced at relatively low costs.
Other objects and advantages of this invention reside in the construction of parts, the combination thereof, the method of production, and the mode of operation, as will become more apparent from the following description.